Biomedical subjects

W E Mesker

Publications and source records attributed to W E Mesker.

4 recordsLinked to original sources

PubMed1989

Discrepancies in ploidy determination due to specimen sampling errors.

Two techniques are described to enhance the detection of low frequency aneuploid cells in automated cell analysis. One method concerns a cell preparation technique; the other is focused on specific cell selection at the measurement level. The cell preparation method has been designed to select and process the tumour areas in paraffin blocks and can be used for image as well as for flow cytometry. The technique uses incident fluorescence microscopy for visual inspection of the surface of the fluorescently stained tissue block to select the specific tumour parts. Using image cytometry, it is shown that in tissue sections with very small tumour foci and many normal cells, aneuploidy could only be detected after enrichment of the cell sample with the specifically selected areas. The cell selection at the measurement level is directed towards detection of low frequency aneuploid cells on microscope slides using the specific capacities of LEYTAS (Leyden Television Analysis System). With this system, cells of interest can be selected by means of minimum size and intensity thresholds. In addition to measurement of the total cell population, all cells above a minimum DNA value can thus be specifically selected and measured. The advantage of both enrichment techniques is the possibility to detect and measure aneuploid cell lines in cases where normal, diploid cells dominate the paraffin tissue.

Aneuploidy↗

PubMed1988

Automated screening for micrometastases in bone marrow smears.

It is possible to detect micrometastases in primary breast cancer using immunocytochemical staining of bone marrow smears. However, using the light microscope the procedure is time-consuming and laborious because such cells occur rarely (less than 1 in 10,000). Using an image analysis system, the Leytas machine, and a specially prepared reproducible slide it has been possible to automate the technique. A 100% concordance was found between the machine and the light microscope in the identification of slides containing moderate to high numbers of tumour cells in bone marrow, and in those containing no tumour cells. However, in those slides containing low numbers of tumour cells (1-10 tumour cells/10(6) normal bone marrow cells) the sensitivity was decreased to 91%. In the presence of non-specific staining the false positive rate was increased from 0% to 22%. This method represents a potential improvement in the assessment of an important clinical staging procedure.

Bone Marrow↗

PubMed1987

Use of DNA image cytometry in addition to flow cytometry for the study of patients with advanced ovarian cancer.

Forty-five patients with advanced ovarian cancer were studied with both DNA flow cytometry (FCM) and automatic DNA image cytometry carried out with the Leiden Television Analysis System (Leytas). There was a significant difference in survival between the diploid and nondiploid cases as determined by FCM. Furthermore, the presence of nuclei with a high DNA content (defined as a DNA content higher than 5C) as determined by Leytas indicated a poor prognosis. When the combined results of FCM and Leytas were taken into account, three different groups of patients could be distinguished. The group of patients with a diploid malignancy (n = 12) had a median survival of more than 60 months. The group of patients (n = 11) with a nondiploid tumor having fewer than 100 nuclei with a high DNA content per 1600 microscope fields formed an intermediate group (median survival, 42 months), whereas the median survival of the remaining patients (n = 22), who had a nondiploid malignancy combined with more than 100 of these nuclei per 1600 microscope fields, was only 15 months. In addition, comparison of the clinical parameters by means of a multivariate analysis (Cox regression model) showed that the combined results of FCM and DNA image cytometry had the largest influence on survival. It is concluded that DNA image cytometry appears to be supplementary to FCM for the study of DNA ploidy abnormalities and that the combined results of these methods have a major influence on the clinical outcome.

Aneuploidy↗

PubMed1987

Preparation of cells from paraffin-embedded tissue for cytometry and cytomorphologic evaluation.

A method is described for the preparation of monolayer smears from paraffin-embedded tissue. The smears are suitable for automated image analysis and DNA measurements while still allowing interpretation of nuclear morphology. The proposed technique uses enzyme treatment and syringing for cell dispersal. The preparation of cell monolayers is performed by cytocentrifugation. After staining the specimens with gallocyanin, nuclear DNA can be measured. Automated DNA measurements using the Leyden Television Analysis System (LEYTAS) showed coefficients of variation of 4.5% for the diploid cell population of suspended benign tissue. After DNA measurements, the specimens are counterstained using orange G and eosin. Since gallocyanin has spectral properties similar to those of hematoxylin, the obtained end product is comparable to specimens stained according to the routinely used Papanicolaou procedure. Using this technique, image cytometry can be applied to paraffin-embedded tissue in combination with conventional cytomorphologic study of the cells.

Cytological Techniques↗